[2] He helped Mobiline to reach a finals stint in 1998 Governors' Cup, but lost in seven games against Formula Shell.
[5] The team was led by imports Derrick Brown, Kelvin Price and Best Player of the Conference winner Rey Evangelista.
Despite this, Gregorio was rewarded, along with then-Coca-Cola Tigers mentor Chot Reyes as co-winner of the PBA Press Corps Coach of the Year Award.
In the 2004–05 season, Gregorio coached the Purefoods team, retooled with amateur stars James Yap, Paul Artadi, Peter June Simon and the vastly improved Kerby Raymundo.
Prior to the finals meeting with Red Bull, he would bring his team back to life after being down 1–3 in the semifinals against Alaska.
Starting center Rommel Adducul was diagnosed with throat cancer and forced Purefoods TJ Giants to trade key player Marc Pingris to San Miguel Beermen for big man Enrico Villanueva.
This signaled a major revamp with Gregorio's team lineup and a losing season finishing with only 15 in 32 elimination round games.
His team would end both tournaments in controversies, a bottle-throwing incident between his player James Yap against assistant coach Koy Banal and the benching of reinforcement Marquin Chandler on separate do-or-die games the TJ Giants consequently lost.
With the return of old reliables Marc Pingris, Paul Artadi together with veteran center Rafi Reavis, and rookie standout Rico Maierhofer, his team would finish as champions in the 2009–10 PBA Philippine Cup Finals defeating the Alaska Aces, 4–0.
In August 2010, Gregorio left B-Meg Derby Ace Llamados and signed a coaching deal with the Philippine Basketball Association returnee Manila Electric Company (Meralco Bolts).
Assortment of injuries to key players, and trades that hurt the team's chemistry contributed to the Bolts downfall.